1. Field of the Invention
The present invention relates to a process for preparing 2-amino-5-cyano-N,3-dimethylbenzamide of formula (I)
by reacting 2-amino-5-cyano-3-methylbenzoic esters or diesters with methylamine, for which the 2-amino-5-cyano-3-methylbenzoic esters or diesters are obtainable from the corresponding bromine compounds by cyanation with copper(I) cyanide. The bromine compounds are simple to prepare by brominating with a mixture of hydrogen bromide/hydrogen peroxide.
2. Description of Related Art
Preparation processes that also encompass the compound of formula (I) are already described in the literature (cf. for example WO 2008/08252, WO 2009/085816, WO 2009/006061, WO 2009/061991, WO 2009/111553, WO 2008/070158, WO 2008/082502) as leading to differing purity and yield.
The present invention accordingly has for its object to provide novel, economical processes for preparing 2-amino-5-cyano-N,3-dimethylbenzamide of formula (I) in higher purity, yield and better quality, especially by foregrounding the purification of the 2-amino-5-cyano-3-methylbenzoic esters or diesters needed for this.